Technology
fNIR Devices
Functional Optical Brain Imaging Systems
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fNIR100 Control Unit and Sensor
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fNIR200 Control Unit, Sensor, Computer/Monitor, Caddy
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fNIR300 Control Unit, Sensor, 2 x Computer/Monitor, Stand
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RXfNIR Replacement Sensor
Technology
fNIR Devices
Functional Optical Brain Imaging Systems
fNIR is an optical imaging technology that measures neural activity and hemodynamic
response in the prefrontal cortex. The subject wears a sensor on the forehead that includes
four IR light sources and ten detectors that are mounted in a flexible band. The fNIR sensor
detects oxygen levels in the prefrontal cortex and provides real-time values for oxy-hemoglobin
and deoxygenated hemoglobin. It provides a continuous and real-time display of the oxygen
changes as the subject performs different tasks.
The fNIR data combines with other physiological variables such as ECG, respiration, cardiac
output, blood pressure, electrodermal activity and stimulus response markers. AcqKnowledge
software provides automated analysis tools for event related potentials and ensemble
averaging. Combining the fNIR data with the other physiological signals provides researchers
with a detailed subject assessment.
The fNIR100 stand-alone functional brain imaging system for continuous NIR spectroscopy
(NIRS) provides an in-lab cognitive function assessment. It eliminates a great many of the
drawbacks of a functional MRI. The subject can sit in front of a computer and take a test or
perform mobile tasks. The system interfaces with most stimulus presentation systems such as
E-Prime, SuperLab, and BIOPAC's range of Virtual Reality systems.
Technology
Functional Near-Infrared Spectroscopy [fNIR]
for natural environments & field conditions…
fNIR100
sensor
Emerging technology to monitor
cortical hemodynamic changes
in response to brain activation
 Safe, affordable, portable
 Noninvasive, minimally intrusive, rugged
Technology
fNIR - Overview of the system
Head Piece
Sensor assembly contains 4 IR light sources and 10 detectors
Operator’s Monitor
Technology
Principles of fNIR I
Neural Activity & Hemodynamic Response
Neurons consume energy (glucose)
when activated
Oxygen is required to metabolize the
glucose
As clusters of neurons are activated,
there is an increased need for oxygen
in that area
Oxygen is transported to neural tissue
via oxy-hemoglobin in the blood
Oxy-Hb and deoxy-Hb are
correlates of brain activity
through oxygen consumption
by neurons
The oxygen exchange occurs in the
capillary beds
As oxy-hemoglobin gives up oxygen to
the neural tissue, it is transformed into
deoxygenated hemoglobin
David J. Heeger & David Ress. (2002)What does fMRI tell us about neuronal activity? Nature Reviews Neuroscience 3, 142-151
Technology
Principles of fNIR II
Photon Migration in Tissue
Source
Detector
Photons that enter the
tissue undergo two
types of interaction:
 Scattering (cell
membranes)
 Absorption
(Hb,HbO2water)
H Obrig , R Wenzel, M Kohl, S Horst, P Wobst, J Steinbrink, F Thomas, A Villringer. Near-infrared spectroscopy: does it function in functional activation studies
of the adult brain? International Journal of Psychophysiology 35(2-3):125-142, 2000
Technology
Principles of fNIR III
Optical Window in Tissue
Stimuli
Presentation
Peak
Oxygenation
Near IR
Initial Dip
Post stimulus
undershoot
 (
Modified
Beer-Lambert
Law

C HB HBO
C HBO2 )L
 (HB
L
HBCHB
HBO22 CHBO
2

I I 0010
)
.G
IIBB




OD
 log
 ((
HB
C HB 

HBO
C HBO22 ))L
OD 
log10
L
10
HB CHB
HBO22 CHBO
II
 C Hb
Oxygenation  C HbO
HbO22
Hb
 CHb
BloodVolume  CHbO
HbO22
Hb
Io
I
Technology
fNIR Signal Processing
Artifact Cancellation (Motion Artifact Removal)
Wiener Filter without Accelerometer
Adaptive Filter with Accelerometer
Subject 5, channel 16
Subject 15, Channel 12
Combined
ICA & PCA
Approach
2000
730nm, Correlation with Reference R=0.90
Reference Measurement
850nm, Correlation with Reference R=0.90
3500
730nm, Correlation with Reference R=0.08
Reference Measurement
850nm, Correlation with Reference R=0.34
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3000
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400
0
50
100
150
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0
50
100
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Izzetoglu M, Devaraj A, Bunce S, Onaral B, “Motion Artifact Cancellation in NIR Spectroscopy Using
Wiener Filtering”, Accepted to IEEE Transaction on BME
450
Technology
Assessment of Cognitive Function
ATTENTION
Target Categorization
Target
fMRI Results
Infrequent Events Transiently Activate Human
Prefrontal and Parietal Cortex as Measured by
Functional MRI
Gregory Mccarthy, Marie Luby, John Gore, And
Patricia Goldman-Rakic. J. Neurophysiol. 77: 1630–
1634, 1997.
Courtesy of Dr. Scott Bunce
Technology
Assessment of Cognitive Function
ATTENTION
Target Categorization (Cont’d)
fNIR Results
fNIR Data
Right
Izzetoglu M, Izzetoglu K, Bunce S, Ayaz, H, Devaraj A, Onaral B, Pourrezaei K
“Functional Near Infrared Neuroimaging”, Accepted to IEEE Transaction on Neural
Systems and Rehabilitation Engineering – Special Issue on Neural Engineering
Left
Technology
Assessment of Cognitive Function
Working Memory (n-back Task)
Courtesy of Dr. Scott Bunce
Technology
Assessment of Cognitive
Function
Working Memory (n-back Task)
Expected Results from fMRI
Smith E, & Jonides J. J. ,
COGNITIVE PSYCHOLOGY 33, 5–42
(1997)
Courtesy of Dr. Scott Bunce
Technology
Assessment of Cognitive Function Working Memory (n-back Task)
Averaged Mean Oxygenation for 9 Subjects
0.150
0.100
0.050
0-back
1-back
2-back
3-back
0.000
1
-0.050
-0.100
-0.150
.2
-0.200
Mean Oxygenation Change
.1
n-back results
performance
>90%
0.0
-. 1
0
1
2
3
NBACK
Results agree with fMRI results from Smith & Jonides, 1997.
Izzetoglu M, Bunce S, Onaral B, “Single Trial Hemodynamic Response Estimation in Event Related fNIR Spectroscopy”, Proc.
of Optical Society of America Conference, 2003
Technology
fNIR APPLICATION AREAS
• Human Performance Assessment
• Depth of Anesthesia Monitoring
• Pain Assessment
• Brain Computer Interface
• Virtual Reality
• Neurorehabilitation
• Autism
• Credibility Assessment (lie detection)
Technology
Human Performance Assessment
To use physiological measures based on fNIR to predict changes in cognitive
workload during a complex cognitive task.
Technology
Depth of Anesthesia Monitoring
Brain Function Monitor for Intra-operative Awareness During Surgery
Surgical subject wearing fNIR Sensor
fNIR
Awareness
Monitor
Technology
Pain Assessment
Brain monitoring system to assess:

Chronic pain

Response to pain medication
Objective assessment of brain response to
pain stimulus
Self Assessment Tool - Subjective
Technology
Brain Computer Interface
ALS, Spinal Cord Injury,
Paralysis…
Target Subject Population:

Amyotrophic Lateral Sclerosis (ALS)

Spinal Cord Injuries/Paralysis

Cerebral Palsy, Muscular Dystrophy

Brainstem Stroke, and others…
Technology
Gaming and Immersive Environments
Enhance 3D experience by enabling users to manipulate and control
objects by thought
Technology
Neurorehabilitation
Quantitative measure to assess the cognitive impairments of
brain injury subjects in their everyday life activities.
Healthy
Subject
TBI
Subject
Technology
Autism
To understand the neurobiological
deficits underlying autism as they relate
to early predictors of the disorder as
well as optimal treatment options.
The fNIR100 system is suitable for
studies in children and adolescents
with autism, because
fNIR100 is not as physically
confining as other imaging
techniques, such as fMRI, and
allows for more movement in
subjects during imaging
fNIR100 measurement points
superimposed
on a subject’s forehead
Technology
Credibility Assessment
Finding neural correlates
of intentional deception
In a modified version of the
Guilty Knowledge Task,
where participants attempted
to conceal the identity of a
playing card, results revealed
increased activation in
bilateral inferior frontal gyri
(BA 47/45) and middle frontal
gyri (BA 46/10) when
participants were lying.
Technology
Contact BIOPAC about
fNIR Devices
Functional Optical Brain Imaging Systems
•
•
•
•
fNIR100 Control Unit and Sensor
fNIR200 Control Unit, Sensor, Computer/Monitor, Caddy
fNIR300 Control Unit, Sensor, 2 x Computer/Monitor, Stand
RXfNIR Replacement Sensor
www.biopac.com
info@biopac.com
(805) 685-0066 8 a.m. – 4:30 p.m. PT